When I plug in an external monitor, Ubuntu doesn't detect its existence and won't output anything to it. The laptop is a Toshiba P50 with the 4th generation i7 and just the integrated intel video card. I've tried both VGA and HDMI monitor connections with the same results. I've also used intel drivers from a PPA and completely removed ubuntu-desktop and deps and reinstalled everything. Others in my office with the same laptop don't have this issue.

output of xrandr and other possibly helpful things (I'll amend as requested):